Snap acting device



March 20, 1951 am. CHRISTENSEN SNAP ACTING DEVICE Filed July 11, 1946 INVENTOR Patented Mar. 20, 1951 SNAP ACTING DEVICE Carlo M. Christensen,-Freeport, Ill., assignor, by mesne assignments, to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application July 11, 1946, Serial No. 682,733

This invention relates to snap acting devices and more particularly to improvements in snap acting mechanisms employed in electric switches of the compact precisiontype which operate in response to very slight movement of the operating member and which operate consistently at the same position of the operating member.

Another object is to produce a snap acting mechanism in which movement of the parts is minimized by constructing the anchor and. actuating member of a single piece that is pivotally journaled for support within the housing wall or base.

Another object resides in the provision of a snap acting device which is highly precise in operation yet capable of being manufactured easily by reason of the fact that tolerances need. be controlled only on two parts: (a) the combined anchor-actuator and (b) a Spring blade having the tension and compression elements integral or permanently affixed to one. another so that in effect they are integral.

A still further object lies in providinga novel snap acting switch construction wherein the tension and compression elements are pivotally enformed on a, rotatable operating memberwhereby making and breaking of the contacts is characterized by a wiping snap action and whereby the switch may be operated with relatively small rotational movement of the operating member.

11 Another object is the provision of a rotary actuated snap acting switch which lends itself particularly to shorting bar construction with the 1 attendant advantages of (a) large capacity in a small switch, (19) .complete isolation ,of electrical and mechanical mechanisms, (a) use of the most.

advantageous spring material without regard for current carrying ability, (dl circuit flexibility, and (e) double break operation. 7

Other objects and advantages will become ap parentirom the following description in connection with the drawings in which- H 12 Claims. (01. 200 -67) Figure 1 is an end view of one modification of the present invention;

Fig. 2 is a side View of Figure 1 showing the outside of the base on which the mechanism is mounted;

Fig. 3 is a side view of Figure 1 opposite to that shown in Fig. 2 showing the parts in one operative position with the upper stationary contact engaged;

Fig. 4 is a view similar to, Fig. 3 showing the parts in their opposite position, with the lower stationary contact engaged;

Fig. 5 is an exploded perspective view of the parts of the switch shown in Figs. 1, 2 and 3;

Fig. 6 is a perspective partial view of another modification showing how a shorting bar may. be applied instead of the movable contact em-;

ployed in the previous figures;

Fig. 7 is an enlarged perspective view of the I combined switch blade anchor and actuating member employed in the previous figures;

Fig. 8 isa sectional view of Fig. 7 taken on the I line 8+8;

Fig. 9 is a view, similar to Fig. 7, of a modifiedform of anchor and actuating member in which the pivot grooves are offset fromthe axis of. ro-

tation to effect wiping action of the contacts with respect to one another when they are engaged or disengaged, and

Fig. 10 is asectional view of Fig. 9, taken on: the line Iii-l8, showing more clearly the offset relation of the pivot grooves with respect tothe rotational axis.

Referring now more particularly to the drawings, the'switch in thepresent instance is mount-' ed upon a base i of insulating material. A suit-, able cover plate (not shown) may be used where desired to protect the working parts from dust or injury from other sources. A switch blade or spring system, generally designated 2, in this instance is made of two parts, a relatively rigid tension element 3, and an inwardly extending resilient tongue or compression element 4 of strip material, both riveted together at common ends away and aninteriorly facing knife or pivotedge is formed. at 8 on one of the 'end portions.

Thev edge 8 and the inwardly facing edge 9 on the end of the tongue 4 are assembled within the pivot grooves I and II in the actuating member I2, the free distance between the edges being formed smaller than the distance between the grooves so that when assembled in this manner the tension element is stressed in tension and the compression element is stressed in compression and the actuating member I2; is, therefore}. effective; to hold the switch blade inplace'without assistance from any other supporting means. The actuating and spring support member I2 may be"- formed by pressing from a piece of fiat: plate material and will have a rectangular or other suitable cross-sectioned end portion I 3 'extendingi through a similarly formedaperture' I4 ii1' the bushing I5 which is rotatablYjournaled within may be engaged by a cam or other driving means to operate the switch.- It will" usually be preferable to insulate" the pin 22" from the internal switch mechanism as byforming the operating lever from suitable insulating material.- A member 23; fastened to the *base by'rivet 24, has

to limit rotatable movement"offth-eiever'z'fl;

The free end' of the switcli' blade is movable between" limiting positions defined by" stops 2'1 and 28;" at leastone" ofwhich is an electrically conducting stationary contact; In the-present instance; where a double throw type ofswitch is illustrated both stops arast'ationary; contacts connectedthrough rivets 29 to" conductingwires 3If and31: The-thirdor common conducting-wire comprisesa=- flexible cable orpigtail" 32" con'-" ne'cted electrically to the switch bladein any suitable manner, for example, by mounting the end"'ofthe-pigtai1 Withinthe'liole 3'3in the'a'ctuating member and' solderin'g orwelding it' in placei mthe-"above described modification the pivot? grooves I 0 and H are substantiallydiametrically positioned withwespeet to the'pivotalaxis of the actuating member I2; that is, the-grooves- III-and" and the pivotal axis A are-substantially parbreaking welds-and cleaning-thecontacts: This ea construction may be' e'ffected by offsetting "a plane containing the grooves) and H from the pivot axis-A,- as shown Figs; and 10''; where* the" groove portion 3 l is ofiset with respectto theend pertion= I32- ope'rating member I i'will' be accompanied bysliding orwiping' movement of*the=movable* contact?- alongthe-stationary c'ontact until the actuating? member is 'rot'ate'd through the maximum stress positionto cause the blade-t0 snap of it's own- 7m;

volition to the opposed contact or stops some cases it" may be: undesirableto electrical current through thdswitch blade' 2 ion example; wherethe? metallic material which: is

Thus,- rotational movement of" the simply: an upper stop to limit the upward. movement of the switch blade. All other parts of such a switch=would bethe same in construction and operatioma's'theswitch already described.

Considering now the operation of the modifiizaticnzishownin Figures 1 through 5, assume first thatlth'ez parts: are in the Fig. 3 position. Currentwill flow between pigtail 32 and wire 30 through the switch blade 2. To operate the switch the lever 20 will be moved toward its stop 26'? This will move groove l l upward and groove I downward' until the groove: I I is intersected: by the tensioncenter: line: of the: tension. ele' ment 2 which will: be approximately" coplanar? with the fastened end of thecompression e16? ment. 4; In casethe: actuating: member I2 is: of the-form shown: in Figs; 9-and:=10, .its rota-e tionwill also cause" wipingmovement': o1 v the contact 5 along the contact: 21 whichtis" benevficial in breaking any weld that may have; 002- curred' between the contacts and-also in: scour.: in'g the. contacting surfaces. Whenl the groove? II intersects the tension center line as above stated, the compression element: will then have "been moved tol its maximum stress. position and:

further: slighti movement past' this position: will. cause:- the: switch blade. to' be; moved: quickly? downwardzwhe'reuponrthe:movable contactffi will: be disengaged froml the stationary contactJJ.

and; be; moved intos engagement with stationary contact Z8'2by: snap action. 'I he parts-will now be in the position shownzin Fig. 4=wherevcurrent can fiow betweenipigtail. 32': and wire 3 I through the: switch v blade 2:. and the: switch" blade: Willa be--maintained in-this-position until the operat' ing; lever minis-moved in the reverse direction. The particular: switch shown is of the non-self returning. typerbut' obviously; the :principles of this; inventionarJe equally," applicable. to a self-returneing spring; constructed as; for. instance, by; pro viding; at separate spring,-member for biasing; the: switch .blade rto either the Fig- 3: or 4: posi-- tion as desired.

The reverse: operation will be exactly thesame as; that; abovedescribed-in. that-( the groove I I will-movei-downwardiw through the: axis of: maxi mum-. stress-after. which? the-movable contact;

will be'snapped:quicklyawayfroln the. stationary contact. 28." and upward into engagement. with. stationary contact 2.1.

While, a I particular form of A the present. invenw tion has beenshown:v as applied. to electric-. switches, it'will be-apparent that itis applicable to. snap acting. devices. generally and that minor changes in the inventionwill readily suggest". themselves ,to others skilled'i'n' the art without' departing from its" spirit and scope. Having thus describedthe invention; what claimed as new'is:

1'; A" map acting switch comprising a pivoted" member; an element pivoted to-saidmemberand carrying a contact" at a fi'ee'endi' said pivotal connection" betweena said member and said elementiiicluding two spaced cooperating groove:

preferred for its physicai -cliaracteristics is axpoor 7&- and edge connections; salii twc' groove" and edge.

connections being on opposite sides of said member and non-diametrically disposed with respect to the pivotal axis thereof, a second contact disposed to cooperate with said first contact, and means for pivotally moving said member to effect snap pivotal movement of said element accompanied by sliding movement of said carried contact with respect to said stationary contact. 2. A snap acting switch comprising a base, a member having one end rotatably mounted in said base and extending therethrough, said member having grooves in its edges parallel to the rotational axis, a switch blade including a cutaway portion and an interiorly disposed resilient tongue, the distance between the end of the tongue and an opposed interior edge being less than the distance between said grooves, said-blade being pivotally supported by the said member by means of the said interior edge and the edge of the tongue resting within said grooves, a contact on the blade remote from the pivotal support, a second contact, means limiting the movement of the free end of the blade, said grooves on said member being less than 180 apart with respect to the pivotal axis to effect wiping make and break action of said contacts, and means associated with said member for pivoting the blade through limited rotational movement of the member to make and break the contacts by snap action. I

3. A snap acting switch comprising a base, a member pivotally engaged by said base, the pivotal axis of said member being substantially normal to said base, said member having a pair of grooves parallel to its pivotal axis, said pivotal axis being positioned to one side of a plane common to said grooves, a switch blade including spaced parallel longitudinally extending tension elements and an inwardly extending tongue or compression element, the distance between the end of the tongue and an opposed interior edge being less than the distance between said grooves, said blade being pivotally supported by the member by means of the said interior edge and the edge of the tongue resting within said grooves, said member having an interior axial portion cut away to clear one of said tension elements, a contact on the blade remote from the pivotal support, a second contact, and means for effecting snap pivotal movement of said member by pivotally moving said member.

4. A snap acting device comprising a pivoted member, an element movable between preselected positions and pivoted to said member by means including two cooperating groove and edge connections spaced on opposite sides of said member but non-diametrically disposed with respect to the pivotal axis thereof, and means for moving said member to effect snap movement of said element between said preselected positions.

5. A snap .acting'device comprising a base, a member pivotally mounted upon said base, an element pivotally mounted upon said member by means including a pair of connections on two sides of the pivotal axis of said member and nondiametrically disposed with respect to said axis, said element being movable between preselected positions defined by stops, said member and said element being compressibly engaged with one another at each of said connections, and operating means including means for pivotally moving said member to move said member and element through an axis of maximum stress to initiate snap movement of said element between i said preselected positions accompanied by slid ing movement of said element with respect to one of said stops.

6. A snap acting switch comprising a rotatably mounted member, a single tension member comprising relatively broad spaced end portions and an integral interconnecting portion disposed along one side of and in a plane at an angle to said end portions, one of said portions carry-,- ing a contact movable between preselected positions and the other of said portionsrformed with a knife edge facing the contact, a compression f member having one end interconnected with the."

end portion of the tension member carrying the contact and having the opposite end in spaced relation with the knife edge, said knife edge and said opposite end. of the compression member being pivotally supported at spaced positions on opposite sides of said rotatable member to stress said tension and compression members, and means for rotating said member between preselected positions whereby to move the knife edge and said pivotally supported end of the compression member through a plane common to said knife edge, said pivotally supported end and said interconnected end and thereby move said contact between its preselected positions with a snap action. a

'7. A snap acting device comprising a base,

the opposite end rigidly interconnected with the second portion of the tension member, said knife edge and said first end shaped to be pivotally supported on said rotatable means, and means operatively associated with said rotatable means on the opposite side of said base for oscillating said latter means between preselected positions to move said pivotally supported knife edge of the tension member and said pivotally supported end of the compression member so that a plane defined by said knife edge and supported end is moved through the juncture between the opposite end of the compression member and the second portion of said tension member to effect snap movement of said second portion a between the preselected positions.

8. A snap acting switch having in combination, a single. rigid tension member formed by-a metal stamping having a cutaway portion alon one side to provide spaced opposed end portions and having the opposite side deformed'out of the plane of the end portions to stiffen the stamping, one of said end portions carrying a contact movable between preselected positions and the other of said end portions formed with a knife edge facing said contact, a resilient compression member overlying said tension member and having one end interconnected with the contact carrying end of the tension member and the opposite end in spaced relation with said knife edge, and a rotatably mounted member shaped to pivotally support the knife edge and the opposite end of the compression member at spaced positions to form a snap spring system having; an axis of maximumi stress, and; means for? rotating: said. member: between. preselected: positionstzsdthatsone of ,saidz'knife edgessand said;

pivotally supported end of the compression memberrmores; through the axis; of maximum stress to effect/snap: movement of; the contaot-,betweet-.i-

preselected: positions:

9. 11123551131) acting device the. combination ofv a thinsheet of insulatingimaterial.forminga base,

an overcenter snap spring system: including ten-- sion: and .compression membersin edgewise relation-to saidibase, means forrmounting and actuatinga' said: snap spring system comprising an actuatingcandisupportimember:includingmeans intermediate-5 its endsfor pivotally mounting the same. ;on.the base, said;means,constituting the sole means forr=supporting'saidzactuating andsupport:

member, a spring; supporting. portion carried on said: mountingrportion and? projecting from one side: of: the: base, said spring, supporting portion having grooves-on opposite sides'for pivotally receiving the-compression and tension'members of theispring systemiandan operating-portion rigid with-said spring supporting portion andprojecting': from the opposite side. of the: base; said-operatingzportion including a lever for rotating and operating. the actuating and support member to moveithe-grooves circumferentially of. the axis of rotation to effect snap action of thespring system, and stops onsaidbasefor-limiting rotation of said, lever between.- prese1ected positions.

10. In a. snap actingdevice, the-combinationof a base, anovercenter snap-spring system including atension' member and a leaf compression memberinedgewise relation to-said ,base and interconnectedxat one'end toform an end free to move between opposed. positions, means for mounting: and actuating said-snap spring system comprising anv actuating and support member includingmeans intermediate its ends for pivotally; mounting'the same on the base, said means constitutingthe sole means. for supporting said actuating'andsupport member, a spring supporting, portion carried on said mounting portion and-projecting from one side of, thebase, said spring; supporting portion having. grooves o n oppositeqsides 'for pivotally receiving theopposite ends. of. the-compression and tension members Of? the spring system and an operating portion rigid with said spring supporting portion andprojeotingzfrom the-opposite sideof thebase, the

operating portionincluding a lever. for rotating:

11. In a snap acting switch;,the combination ofs a,thin sheetof insulating material forming a base, an overcenter snap spring systemadjacent one. side. of said base including tension and leaf compression membersin edgewise relationtosaid base,. av spring support projecting; outwardlyfrom and rotatable about an;axisnormal to said base,

said:v spring, support, having; grooves; on opposite;-

otally supported means against axial movement, 1 relative to the; base,, an operating portion rigid with saidgpivotally supported means-andiprojecting' outwardly from-the-opposite side of thebase, said operating portion including a-lever engage? able-ion rotating said pivotallysupported means; t and; said. spring; support to move the grooves.

circumferentiallyof the axis oft-rotation to eirect-v snapflactionofthespring system;

12.- In. asnap; acting switch, .thev combination of athinsheet of insulatingmaterial forming a,

base, an 1 overcenter snap spring system; adj acent,

one side of 1 said baseincluding tension and: compression, members interconnectedI at. one end; toform-an end free to-move between opposed-positions, at leastone ofsaid members being a leaf like; member iniedgewise relation to said baSe a: mobile contact-mounted on said free, end, aspringg support projecting outwardly from and rotatable. about. an axis: normal. to saidbase, said spring. support having grooves on OPPOSHQ SidESgfOI. piv-- otally receiving the opposite ends 4 of:v the tension;

and compression. members of: the; spring systemi. and forming the'sole support for said springrsystern, pivotally supportedrmeans mounted on said.

base and; providing the sole supportv for: said; spring support; means acting ;between said: last mentioned means and thebase for: holding said; pivotally supported means against. axial move.- mentrrelativato thebase, an v operating portion rigidwith said pivotal1y= supported means; and projecting; outwardly fronrthe opposite, side of: the base; said operating;portioniincluding. azlever. engageable for rotating. said; pivotally, supported; means and, said: Spring support to. move the.- grooves.circumferentially of the axis ofjrotation;

. to efiects-nap action of :the-mobile contact-,spaced,

fixed: stops; mounted on the. base for limiting; movement'ofsaid free end; atqleast one-oii said! stops beingdefined by a fixedcontact adaptedgfor.- connection to .an. external circuit and a flexible; connector connectedtdsaidspring support for, connection to an external, circuit.

CARLOYM; CHRISTENSEN:

REFERENCES;- CITED.

The-following references are of recordin'thefile of this patent:

UNITED STATES. PATENTS Number Name Date 1,393,111 Getchell Oct. 11,192.13 1,719,096 Burke July 2, 1929: 1,848,171 Hanel Mar; 8,1932- 1,983,076 Getchell Dec. 4,.1934 2,095,222 Wilms Oct. 5, 193.7 2,135,864 Weber Nov. 8, 1938 2,295,463 Fetter Sept. 8, 19,421- 2,314,714' Kouyoumjian Mar. 23, 1943' 2,402,838 Obszarny June 25, 1946. 2,476,103 Martin July 12,1949.- 

